Air speed responsive device



1955 M. J. B. RUSSELL 2,699,066

AIR SPEED RESPONSIVE DEVICE Original Filed Aug. 30, 1945 INVENTOR. MATTHEWJ. B. RUSSELL United States Patent AlR SPEED RESPONSIVE DEVICE Matthew J. B. Russell, Brooklyn, N. Y., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Original application August 30, 1945, Serial No. 613,636. Divided and this application October 5, 1950, Serial No. 196,441

2 Claims. (Cl. 73-182) This invention relates to an airspeed responsive device, and this application is a division of application Serial No. 613,636, med August 30, 1945, which matured into U. S. Patent No. 2,530,003, on April 24, 1951. The instant invention is particularly directed to an arrangement for etl'ecting airspeed and/ or mileage indications in which the movement or the pressure responsive diaphragm actuated by impact pressure obtained H0111 a Pitot tube is applied to a lever system for controlling the opening and closing of a shutter m the fluid circuit of a turbine. The turbine drives a centrifugal means having a linear movement which is imparted to a lever system to counterbalance the ettect ot' the pressure responsive diaphragm on the lever system in controlling the movement of the shutter.

Another ODJeCI or the present invention is to provide an airspeed responsive device of the character described in which the pressure responsive diaphragm of an airspeed indicator 1s used to control the centrifugal means.

still another ob ect of this invention is to provide an airspeed responsive device or the character described with a compensating member to correct for varying air density.

arm a further object of this invention is to provide an air mileage indicator of the character described in which the centrifugal means may be driven by a turbine, the fluid circuit or the turbine being controlled by a shutter in the exhaust outlet, the shutter being adapted to be opened and closed by the unbalance and balance of the lever system.

Yet another object of the present invention is to provide a highly improved air mileage indicator of the character described which shall be relatively inexpensive to manufacture, positive in its operation, and practical and etncient to a high degree in use.

Other objects of this invention will in and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter described, and of which the scope of this application will be indicated by the appended claims.

in the accompanying drawing in which one embodiment of the present invention is illustrated, the single drawing is a diagrammatic view of an airspeed responsive device in which an air turbine is used to drive a ball governor.

Referring now in detail to the drawing, 11 designates an airspeed indicator of the conventional type comprising a pressure responsive bellows 12 within a casing 13. The interior of the bellows 12 is connected by a pipe line 14 to the impact or dynamic pressure source of a Pitot tube. The interior of the casing 13 is connected by lines 15 and 15A to the static pressure of the Pitot tube. The lower face of the bellows 12 is provided with a rack 16 adapted to be moved up and down upon expansion and contraction of the bellows. Fixed to a horizontally disposed shaft 17 which extends beyond the rear of casing 13 is a pinion 18 positioned within the casing and engaging rack 16. Rotation of the pinion by movement of the rack will rotate shaft 17 and a pointer 19 over the face of the dial 20 of the instrument by way of a gear sector 21 fixed to shaft 17 and a gear 22 fixed to a shaft 23 on which pointer 19 is fixed. A reading of the pointer 19 with respect to the dial 20 will give indicated airspeed. Fixed to the extreme of shaft 17 is a pinion 24 adapted to mesh with a rack 25.

Pinion 24 fixed to the shaft 17 and actuated by the part be obvious airspeed indicator bellows 12, moves the rack 25 up and down to rotate a lever 51 pivoted as at 52. The other end of lever 51 is provided with the pin 34 which registers in the peripheral slot of member 33 of a ball governor 32. Pivoted as at 53 on lever 51 is a rod 54; the lower end of which is pivoted as at 55 on an arm 56. Ann 56 in turn is pivoted as at 57. The free end of arm 56 has pivoted thereto a depending rod 58, the lower end of which is connected to a conventional shutter or valve 59 placed in the exhaust outlet 60 of the air turbine 50. A source of air pressure-(not shown) is connected to the air turbine through the inlet 61.

In operation,rotation of the lever 51 in a counterclockwise direction by the expansion of the bellows 12 will move the rod 54 downwardly to rotate the arm 56 in a clockwise direction. Clockwise rotation of the arm 56 will move the shutter 59 downwardly to open the exhaust outlet 60. The air flow through the turbine 50 is thereby unrestricted, permitting the turbine to operate the governor 32. At the predetermined speed, the linear movement of the peripheral member 33 will rotate the lever 51 in a clockwise direction, thus moving the shutter 59 upwardly to restrict the air flow through the turbine 510. dThe speed of the turbine operation will thus be reuce The airspeed responsive device is also compensated for the changes in air density. An evacuated compensating bellows 41 in casing 42, subjected to the static pressure of the Pitot tube by way of hue 15, is connected to an upstanding rod 62 which is connected by way or pivoted lever 63 to the arm 56. Expansion of the compensating bellows 41 will oppose the ball governor 32 in raising the shutter 59 to restrict the air flow through the turbine 50.

The lower end of shaft 31 as influenced by the density compensator aneroid 41 may be connected by any suitable gearing (not shown) to a tachometer (not shown) or other suitable device to indicate true airspeed. The shaft may also be connected by suitable means to a Geneva mechanism (not shown) or any other indicating means to indicate the air mileage of the craft over a period of time.

While the above description has been limited to an air turbine, it can be readily appreciated that a fluid turbine could be used in its place and stead.

It will thus be seen that there is provided an airspeed responsive device in which the several ob ects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments may be made of the above invention, and as various changes might be made in the embodiment disclosed herein, it is to be understood that all matters set forth, or shown in the accompanying drawing, are to be interpreted as illustrative, and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. An airspeed responsive device, comprising an airspeed indicator having a pressure responsive member actuated by the impact and static pressures of a Pitot tube, a lever system actuated by the expansion and contraction of the pressure responsive member, a ball governor, a

fluid motor having an inlet and an outlet to rotate said' ball governor, conduit means for conducting pressure fluid to the motor inlet, a shutter in said motor outlet positioned to be opened and closed by said lever system, said lever system including a first lever pivoted intermediate its ends and connected at one end to said pressure responsive member and to said ball governor at its other end, a second lever pivoted at one end and connected to said shutter at its other end, and a link connecting said second lever to said first lever intermediate said one end of said first lever and its pivot, the linear movement of said ball governor being applied to said first lever of said lever system to balance the force applied thereto by said pressure responsive member to move said second lever to open and close said shutter to control the speed of rotation of said ball governor at a speed proportional to air speed, and a second pressure responsive member actuated by static Pitot pressure coacting with said second lever of said lever system to compensate the rotational speed of said ball governor for varying air densities.

2. In an airspeed responsive device, the combination comprising an air speed indicator having a pressure responsive member actuated by the impact and static pressures of a Pitot tube, a ball governor, a fluid motor having an inlet and an outlet to rotate said ball governor, conduit means for conducting pressure fluid to said motor inlet, a shutter in said motor outlet positioned to be opened and closed to control the rotation of said motor, a lever system including a first lever having a pivot intermediate its ends and connected at one side of said pivot to said pressure responsive member and at the other side to said ball governor, a second lever having a pivot at one end and connected at its other end to said shutter and intermediate its ends to said one side of said first lever, the linear movement of said ball governor being applied to said first lever of said lever system to balance the force applied thereto by said pressure responsive member to move said second lever to open and close said shutter to control the speed of rotation of said ball governor at a speed proportional to air speed.

References Cited in the file of this patent UNITED STATES PATENTS 

